RICHMOND, Va. — Republican Lt. Gov. Bill Bolling said Wednesday that he would not run for governor in 2013, citing the state party’s decision to choose its nominees through a convention instead of a statewide primary.

Bolling’s decision leaves conservative Attorney General Ken Cuccinelli without major opposition for the GOP nomination at the June convention, but ignited speculation whether Bolling would launch an independent candidacy.

It also means a likely showdown in next fall’s gubernatorial election between him and Terry McAuliffe, the longtime associate of former President Bill Clinton and the only Democrat to announce his candidacy so far.

Bolling nurtured gubernatorial ambitions for years, since his election as lieutenant governor in 2005.

Four years ago, he put aside his own plans to run for governor, seeking a second term as lieutenant governor while supporting fellow Republican Bob McDonnell for governor. In exchange, McDonnell was strongly supporting Bolling over Cuccinelli for governor next year.

Cuccinelli entered the race unexpectedly a year ago after saying in interviews beforehand he expected to seek re-election. Then in June, the state Republican Party’s rulemaking central committee — freshly stocked with conservatives friendly to Cuccinelli — changed the nomination method to a convention, virtually assuring Cuccinelli’s victory.

“For the past several months my campaign team has worked hard to restructure our campaign to effectively compete in the convention process. While we have made a great deal of progress, I reluctantly concluded that the decision to change the method of nomination from a primary to a convention created too many obstacles for us to overcome,” Bolling said in a statement.

He said he also was concerned that deep divisions in the party could be created by a prolonged campaign between Cuccinelli.

“The convention process would have forced Republican activists to take sides against their friends in local committees all across our state,” Bolling said. “The wounds that can develop from that type of process are often difficult to heal.”

Cuccinelli — a hero to Virginia tea party groups for challenging Obamacare in court and hounding a former University of Virginia climate change researcher — was delighted by Bolling’s decision. It leaves Cuccinelli facing only Tareq Salahi, a Virginia vintner and onetime reality television figure who gained fame by crashing a White House party three years ago with his wife, Michaele. The couple has since divorced.

“Throughout this race, I have kept to the premise that Bill and I are allies in governance, even if temporary competitors in politics,” Cuccinelli said in a press statement issued by his campaign committee.

But Cuccinelli won’t find an ally in Bolling, who was deeply disappointed by Cuccinelli’s decision a year ago to challenge him for governor. Bolling told The Associated Press he would not endorse Cuccinelli or anyone else.

“I have serious reservations about Mr. Cuccinelli’s ability to effectively and responsibly lead this state,” Bolling said.

His statement announcing his withdrawal provoked questions about whether Bolling would pursue an independent or third-party bid for governor, something certain to dilute conservative support for Cuccinelli in a race with McAuliffe.

“I intend to remain actively involved in the 2013 campaigns – perhaps not as the Republican nominee for governor, but as a more independent voice, making certain that the candidates keep their focus on the important issues facing our state and offer a positive and realistic vision for effectively and responsibly leading Virginia,” he wrote in the statement.

Bolling told the AP he didn’t mean to imply a nascent independent candidacy, something that would be difficult to finance with only marginal odds of victory. But he said he would not rule out a three-way contest next fall should the right circumstances arise.

“I have no current intention to run as an independent, but I learned a long time ago that in this business you never say never,” Bolling said.

“Conventions are by their very nature exclusive, and at a time when we need to be projecting a positive image and reaching out to involve more Virginians in the Republican Party, I am unwilling to be part of a process that could seriously damage our image and appeal,” Bolling said in Wednesday’s statement.

The mortal blow came Nov. 6 when Republican Mitt Romney’s defeat in the presidential race eliminated any prospect that McDonnell would exit early for a possible White House post, allowing Bolling to finish McDonnell’s term and run next year as the pro-jobs incumbent.

Virginia Democrats immediately tried to tie Cuccinelli’s strong anti-abortion positions to those of Republicans who flamed out in high-profile Senate races this year after gaffes about reproductive rights issues: U.S. Rep. Todd Akin of Missouri and Richard Mourdock of Indiana. Akin said in an interview that women’s bodies developed natural defenses that blocked conception after “legitimate rape,” and Mourdock said in a debate that pregnancies resulting from rape are “something that God intended to happen.”

McAuliffe, a former Democratic National Committee chairman and close friend, fundraiser and confidante to both former President Bill Clinton and Secretary of State Hillary Clinton, this month announced his second gubernatorial bid. In 2009, McAuliffe and his bitter intraparty rival, outgoing state Democratic Party chairman Brian Moran, savaged each other in a three-way gubernatorial primary that state Sen. R. Creigh Deeds won. McDonnell routed Deeds.

“It is disappointing that more mainstream Virginia Republicans are being driven out of leadership by the far-right,” McAuliffe said about Bolling’s decision. “Virginia voters have repeatedly made clear that they prefer mainstream leaders building consensus instead of politicians pursuing their own ideological agenda.”